Internal combustion engine



July 25, 1939.

H. A GEHRES INTERNAL COMBUSTION ENGINE Filed June 3, 1937 3 Sheets-Sheet 1 INVENTOR HewzZYA. fiekres I $416 w M ATTORNEYS July 25, 1939. "H. A. GEHRES 2,166,930

INTERNAL COMBUSTION ENGINE Filed June 3, 1937 3 Sheets-Sheet 2 ii I? IiE \I 46 7 44 //////A (f l? 7IIIIA 1/1/1111,

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BY 2 w a M22! July 25, 1939. H. A. GEHRES J ,1 I

INTERNAL COMBUSTION ENGINE Fi led June}, 1957 3 Sheets-Sheet 3' nlcz/ mam: Z6

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ATTORN'EYS 7 Patented July-2 5, 1939 UNITED STATES PATENT OFFICE INTERNAL COMBUSTION ENGINE Hewitt A. Gehres, Mount Vernon, Ohio, assignor to Cooper-Bessemer Corporation, Mount Vernon, Ohio, a corporation of Ohio Application June 3, 931, Serial No. 148,185

9 Claims.

10 by the action of the power piston during its compression stroke: "This charge is compressed during the expansion stroke of the piston and near. the end of the expansion stroke when the intake'and exhaust ports are both opened, the

mixture of gas and air flows into, and to some extent through the cylinder, forcing out the burned gases and leaving a mixture in the cylinder of widely varying and often unsatisfactory combustion characteristics. Regulation of such prior engines has been effected by way of varying the quantity of gas admitted with the air and since the quantityof air admitted remains practically constant, the percentage of gas in the mixture varies widely. Since for ideal or even satisfactory combustion conditions, this percentage has to be kept within a very narrow range, it is evident that at light loads and also at extremely heavy loads, the mixture becomes either too lean'or too rich to giveproper combustion. As a result, in prior two-cycle engines the firing is intermittent and the operation of the engine is irregular and uneconomical. The low ecenomy of this type of engine is not only caused by irregular operation, but also because of the" scavenging being done with a mixture of air and gas, a substantial part of the gas escapes through the exhaust ports unburned. According to the present invention, an engin construction and method of operating the same 40' isprovided whereby scavengingv air may be admitted at one end of the cylinder or combustion .chamber and the burned gases vwith some air may be exhausted at or adjacent this same end of the chamber, but meanwhilethe fuel may be admitted at the other end of the chamber, or

at a point remote from the air intake and exhaust ports, in a manner such that no valuable amount of unburned fuel escapes. Furthermore. with the preferred form of the present invention,

5 the gas or other fuel admitted to the cylinder may be admitted into two different zones within the combustion chamber, one of the zones for example being supplied with a fuel and air mixture having substantially the ideal percentage 5d of fuel for prompt and substantially perfect combustion, and the other zone being supplied with a quantity of gas or other fuel in which the percentage of fuel is generally too great for ideal combustion conditions The amount of fuel admitted to this second zone may be widely varied to meet diflerent loads: Then with this arrangement and method, the atmosphere within the combustion chamber is more or less stratified, i.- e., with first astratum remote from the air intake and exhaust ports, comprising substantially an ideal combustible mixture, second a stratum embod ng a variable quantity offuei generally too rich f r ideal combustion, and third a stratum or volume of air remaining from the scaven in operation. Then upon compression of 1 these strata, ignition and combustion of the first causes the second stratum to be forced into admixture with the air stratum and at some moment as the second stratum is being mixed with the air, conditions will be ideal for thorough combustion of the fuel of the second stratum. With this operation, regular firing even with widely varying loads is insured and with no subs stantialloss of unburned fuel.

by apparatus forming a part of the engine itself, or if desired, these two fuel supplies may be provided from pumps with valves suitably timed to deliver the respective charges after the cylinder exhaust ports are closed, so as to prevent any loss of unburned fuel to the exhaust. fAlso in some cases if; desired, both of the separate fuel supplies may be varied either manually, or

automatically by well-known governing appau ratus.

Various further and more specific objects, features and advantages will clearly appear from the detailed description given below taken-in connection with the accompanying drawings which form a part of this specification and illustrate!" merely by way of examplea'preferred form of the invention. The invention consists in such novel features, arrangements, combinations of parts and methods as may be shown and described in connection with the apparatus herein disclosed. In the drawings, Fig. 1 is a sectional view of an engine embodying one example of the invention, this section being taken longitudinally of the cylinder;

Fig. 2 is a sectional view taken substantially along the line 22- of Fig. 1';

Fig. 3 is an enlarged view of a portion of Fig. 1, certain parts being shown in further sectional I detail;

The two suppiles of fuel may be compressed and admitted 25 a cylinder ll with a cylinder head ll formed 4 is a further sectional view taken substantially along the line 4-4 of Fig. 1; and

Fig. 5 somewhat schematically indicates conditions in the engine cylinder at the beginning of compression of the fuel charges.

The engine as shown in Fig. 1 may comprise with an elongated cavity or chamber as at i2 comprising an extension of the combustion chamber including ,the cylinder. A piston is shown at I I connected to a pistonroii I, which.

in turn may be connected as by across head II and connecting rod it to a crank shaft 11. The cylinder may be substantially surrounded by a suitable water Jacket or other cooling means. I'for example, as here shown, cooling fluid cavities are provided as at It and I8 surrounding respectively the cylinder and the elongated cav- Air may be admitted through an adjustable butterfly valve to a cavity 2|. When the piston is moving on its compression stroke, this air will be drawn through a 'suitable form of flap check valve 22 into a chamber 23. This chamber may be closed in respect to the crank case by 'any suitable means such as a flanged member der. exhaust port 25 will be opened and soon thereafter an air intake port 26 will be opened,

thus admitting the compressed air into'the cylinder for scavenging purposes. The face of the piston may be shaped as shown, so asto suitably deflect this air into the cylinder and to cause thorough scavenging, and whereby some of this air, together with the burned gases, are forced out through the exhaust port 25.

At the of this scavenging operation,

means is also provided as hereinafter described,

for supplying a quantity of a substantially ideal combustible mixture within the upper end or zone of the elongated cavity l2, and also a variable 'quantity of raw gas or other fuel generally too rich for perfect combustion, into a lower zone of the cavity l2. The two supplies of fuel thus separately admitted to these zones will be more or less stratifled within the chamber extension l2, and the scavenging air and burned gases during the scavengingoperation will'have little op-- portunity to mix therewith, and thus exhaust of unburned fuel through the port 25 will be avoided.

Referring now. particularly'to Figs. 2 andi, a

chamber 21 may be provided for receiving quan-.

titles of an ideal combustible mixture, for exam ple, of air and gas. A chamber 28 may be provided for receiving quantities of fuel, for exam-.

,ple raw gas, in amounts varied according to the load effective on the engine or the desired speed thereof. Generally the fuel admitted through chamber 28 will be too rich for ideal combustion. The same or different kinds of fuel may be admitted to the chambers Hand 2. respectively, but normally the quantity of fuel admitted to thesechambers will diflenas will also the perv centage of fuel present. If 'the fuel used comprises gas of the type ordinarily used with engines of this, class, then the gas for the mixture in chamber 21 may be supplied through a pipe or nozzle 2!, connected through a valve 30 to a suitable source of supply. Air supplied through an inlet ii becomes mixed with this gas within a cavity 32 connected with the chamber 21 through a suitable check or flap valve 33. The raw gas or other fuel for the chamber 22 may be admitted througha supply pipe 34 having a butterfly valve 8! for varying the supply of fuel entering a cavity 30. The cavity 38 may be connected with the chamber 28 by a valve 31 similar to thevalve 23. The butterfly valve 35- may be operatively connected to a governor in any of fuel passed may be varied in accordance with the load effective on the engine.

Referring to Figs. 1 and 2, it will be noted that theair chamber 23' is provided with an extension cavity 23' for communicating with the air inlet port 2; The extension cavity 23' may also be. brought into communication with the chambers 21 and 28 through apertures as at 38 and 38 respectively. 'Thus as the piston draws air into the chamber 23 through valve 22, as above described, it will also cause air to be drawn from chambers 21 and 28 through apertures 32 and It. This in turn will cause quantities of the fuel or fuel mixture to be drawn from cavities I2 anti since the cavities 21 and 28 are relatively elongated, the amount of fuel drawn in will be in-- sufficient to cause the fuel to pass into the chamber extension 23'. Yet a fixed amount of the ideal combustion mixture will be drawn into the chamber 21, but this amount will be insumcient to ill! the'entire length of this chamber. And

a variable charge of the raw gas or other fuel is similarly drawn into-the chamber 28, but duetothe elongated form of this chamber, it will not be entirely filled with the charge when the compression stroke of the piston is completed,

enging air and become mixed therewith.

' Now, when the piston moves on its expansion stroke, compression of the 'air within chamber 28 will cause air pressure to be supplied through chamber extension 23 and apertures 38 and 3! to the fuel or fuel mixtures within chambers 21 flap valves as at 4! and ll, into passages 42 and '0 respectively. We now have in passage. 42 a o,

predetermined charge of an ideal combustion mixture under pressure. And passage 43 also contains under pressure a suitable charge of raw 4 gas for example, sufficient to complete the fuel requirements for the next stroke of. the engine. 5

At the time thatthe air intake and exhaust ports 2! and 2| are uncovered, the pressure in the cylinder drops sufllciently so that the two fuel charges in passages l2 and' force their way through valves as at 44 and ll respectively, into the zones surrounding the outlets of these valves within the combustion chamber extension l2. The valves N and It maycomprise any suitable well-known type of free poppet valves.

As the movement of the piston proceeds with its next compression stroke, the air intake port 28 will first be closed, and shortly thereafter the exhaust port 25 will be closed and the main body of the cylinder will contain a stratum of air.

Next to this stratum will be a stratum of fuel bustible mixture will belocated in the upper end of the extension I: surrounding a spark plug as suitable well-known manner so that the amount 36' into chambers 21 and 28. However,

aioepso proper moment of compression of the three strata. 'Then the initial combustion of the mixture within the upper end of extension I! will immediately cause the next stratum. over-rich in fuel, to become admixed with the air stratum.

At the moment when this mixing has progressed to the extent of giving a highly combustible mixture, the burning of the ideal mixture stratum will promptly cause combustion of the remainder of the charges to proceed to substantial com- 'pletion. v

The term "gas as used in the appended claims is intended to comprehend atomized fuel as well as fuel in strictly gaseous condition.

While the invention has'been described indetail with respect to a particular preferred example, it will be understood by those skilled in the art after understanding the invention that various changes and further modifications may be made without departing from the spirit and scope of the invention, and it is intended therefore in the appended claims to cover all such' changes and modifications.

What is claimed as new and desired to be so cured by Letters Patent is:

1. The method of operating an internal combustion engine which comprises establishing within an explosion chamber thereof, a stratum of a readily combustible gas and air mixture another stratum containing a substantially greater proportion of gas, and still another stratum comprising air, and igniting said first named stratum whereby the explosion thereof causes the othertwo strata to merge and explode, and varying the power produced by adjusting the quantity of gas in said second named stratum, while maintaining. the proportions of gas and air in said first named stratum within limits to insure therein, prompt and thorough, combustion upon ignition.

2. In a two stroke cycle internal combustion engine, an explosion chamber with a reciprocatport adjacent one end of the cha'mberfor introducing air under pressure, means for concurrently discharging products of combustion from the chamber, including an exhaust port adjacent saidend but spaced from said intake port,

' said ports being closed by the piston except when the piston is adjacent its extreme position at said end, means for introducing gas or a rich gas mixture into a zone adjacent the other end of the chamber when the piston isadjacent the first named end of the chamber, means for then also introducing a gas mixture highly favorable to combustion into a second zone adjacent said first named zone in the chamber, and ignition meanslocated in said second zone and actuated when the piston has compressed the gas and gas mixtures in said zones. 1

3. In an internal combustion engine, an explohaust port spaced from said intake port, means a for introducing gasor a rich. gas mixture into a zone of said chamber spaced from said ports, means for then also introducing a gas mixture highly favorable to combustion into a second zone adjacent said first named zone in the chamber, and ignition means located in said second zoneand operable when the piston has compressed the gas and gas mixtures in said zones.

4. In a two-stroke cycle internal combustion engine, an explosion chamber with a reciprocatingpiston therein, means including a surface of said piston external to said chamber for providing a'supply of air under pressure, means utilizing said pressure to provide supplies of gas under pressure, means also utilizing said pressure to provide supplies of a readily combustible gas mixture under pressure, and means for admitting said air, said gas, and said gas mixture, sep arately at spaced points into the chamber, in predetermined timed relationshipa:

5. In a two-stroke cycle internal combustion .engine, a cylinder, a reciprocating piston there'- in, means for admitting and exhausing scaveng ing air adjacent one end of said cylinder, and means adjacent the other end of the cylinder for admitting two difierent combustion fiuid medium at separate points, in substantially a predetermined timed relationship with the admission and exhaustion of the scavenging air.

6. In a two-stroke cycle internal combustion engine,a'cylinder, a reciprocating piston therein, a gas chamber, an air chamber communicating with said .gas chamber, means whereby the piston on its compression stroke draws air into said air chamber and gas into said gas chamber, a second gas chamber, means whereby said piston on its expansion stroke compresses said air and said air forces said gas into said second chamber, and means whereby approximately at the termination of the expansion stroke, the

compressed air is admitted to the cylinder and engine, a cylinder, a reciprocating piston therein, a gas chamber, a gas mixture chamber, an air compression space communicating with bothof said chambers, means whereby the piston on ing piston therein, means including an intake its compression stroke draws air into said space, and gas and a gas mixture into said chambers respectively, means whereby said piston on its expansion stroke compresses said air and said 50 air applies pressure to said gas and gas mixture, and means whereby approximately at the termination of the expansion stroke, the compressed air, gas, and gas mixture, are separately admitted to the cylinder.

8. In an internal combustion engine, a-cylinder, a reciprocating piston therein, a pair of chambers for receiving two difi'erent combustion mediums, an air compression space communi eating with both of said chambers, means whereby the piston on a compression stroke draws air into said space and two different combustion .modiums' into said chambers respectively, a second pair of chambers, means whereby said piston on its expansion stroke compresses said air and said air forces said combustion mediums respectively into said second pair of chambers, and means for then admitting the compressed air and said combustion mediums respectively at three spaced points into the cylinder.

9. The method of operating a two-stroke cycle internal combustion engine which comprises establishing within an explosion chamber thereof, a stratum comprising air adjacent the mov- I chamber, a second stratum o! a relatively com bustible gas and air mixture in a region within 7 the chamberlremote from said power transmit ting element, and a third stratum in the region between the two first-named strata, said thirdnamed stratum being too rich in combustible -gas to insureready ignition and being introduced separately from but substantially concurm' rently with the introduction oi the second-- ,named stratum. igniting said second-named stratum whereby the explosion thereof causes the other'two'strata to merge and explode. and varyingthe power produced by adjusting the quantity or gas in said third-named stratum,wwhile maintaining the proportions or gas andair in the second-named stratum within limits-.tp insu're therein prompt and thorough combustion upon ignition,

imwi'rr A. Grimm's; 1o 

